Solar Battery Connections Explained: Series Vs. Parallel // Wiring Off Grid Power Systems

so you want to combine your batteries into a battery bank and you're wondering what the best option for you is to get the best performance and the lifetime are you going series parallel combination of the two where do you mount them how do you mount them well in this video I'll run you through the basic principles how to connect your batteries into a battery bank I'll tell you what to look out for what to avoid and I'll give you a few tips and tricks what you can do in order to improve the lifetime of your battery bank so let me start by introducing myself my name is Jesse I am a renewable energy engineer I have run several companies and a design and installation of battery based off-grid solar energy systems I have held the position of energy officer for the United Nations and I founded the company solar solution through wages share my knowledge and expertise through videos such as this one online articles and I provide personal direct support through services on my website ok so let's get started throughout this video I'll provide you the information in 3 different sections so we'll look at series parallel combination of the two how to connect your battery into a battery bank we will then look at how to get the best performance out of your setup and of course I'll tell you how to get the best lifetime out of your battery bank so let's look at series versus parallel now the first thing I want to say is that whatever you do series parallel combination stack them on top of each other put it next to each other whatever you do you will not change the total amount of energy that will be in your battery bank that always stays the same if you connect your batteries in series you take the positive from one battery leave it into the negative of the other one then take the positive lead into the negative you go on like this and you build one string of batteries then the positive and negative of this battery bank you'll lead it into your system if you connect your batteries in series the total voltage will go up but the empower rating will stay the same that the advantage is that you can typically use smaller wire sizes another advantage from such a setup is that solar charge controller which are rated on the amperage rating they will still work at the same max amount of amperage but if you double tripled or quadrupled your system voltage the power output of the solar charge controller or increase proportional to the increase of your system now if we look at the parallel connection you would kind of place the batteries side-by-side you connect all the negatives together all the positives together and these two would then go into your system and such a set up the voltage you would stay the same but the empower rating would increase proportional to the amount of batteries that you place next to each other so a typical advantage of parallel connection of batteries is that you can still use your low voltage DC appliances that you would have in your boat your RV or your cabin and connect them straight to your battery mech now disadvantage of parallel connection is that you're keeping the voltage is same but your amperage might go up and if your amperage goes up you will have to increase your wire sizes I've got other videos produced about this so if you're interested in check them out now the other option of course is to combine the two setups so you you connect batteries in series take other batteries connect them in series and then combine these two groups of batteries into a parallel battery pack okay so we move on to the next topic I will look at how to get the best performance out of your system I will mention three different things which I think are important for you to know the first one is what I refer to as a mirrored setup if you have batteries connected in parallel you would want each in every set to be exactly the same so this is important because you want each and every battery to do exactly the same amount of work you don't want one battery to perform a little bit more than the other one you don't want one battery to have to work less hard than the other one the way in which you can accomplish this is by using exactly the same wire sizes the same length of wires same connectors the same batteries the same battery ages and installing them in the same temperature zone now if you cannot install all your batteries in the same location you have to take one or more batteries in place and further away what you really have to do is make sure that the length of the wires are all identical so you might end up with some batteries that have an excess wire just coiled up and laying there somewhere this might look funny but it is really something that you want to do now the second thing I want to mention is that as the temperature of battery increases the capacity also increases slightly but the lifetime of batteries reduces drastically with increasing temperatures so what you want to do is whatever you can to keep the battery temperature low easy ways for example is providing ventilation the overall battery compartment or making sure that the batteries are not flush against each other but have let's say an inch or a few centimeters of space in between them so the last thing I want to say is regarding how you mount them and where you mount your batteries more enough then I can see batteries and RVs and boats that are not fixed to anything and this is a significant performance and safety concern so make sure you strip them down or fix them in whichever way you prefer make sure they cannot move and if you have the let acid flooded batteries remember that they can and they will produce harmful gases so make sure that there's always a way ventilation and wherever you install your batteries so let's go to the last topic we're going out to get the best lifetime out of your battery now a very important thing if you have the flooded lead-acid batteries make sure please make sure that always always always the internal parts of your battery all the metal bits and pieces are always submerged in the electrolyte in the liquid and this is especially true for the sailors among us with the monohulls if you are tilt still then all the part in your battery should be completely submerged now the other thing I want to mention is that connections can work a little bit on the varying temperatures and time etc so if you have recently reconnected some cables and wires then it will be a good idea after a couple of months to recheck everything just you know walk it through and retighten everything to make sure that there are no loose connections and the last thing and a very important one always keep it cool lower battery temperatures will give you longer life time so whatever you can do to reduce the battery temperatures please do it and you'll get more life out of your battery bank ok so now a question for you if there are other topics that you'd like to learn more about let me know in the comments below and I'll use this as inspiration to provide more videos for you and for others and of course if you liked it I would really appreciate if you can give me a thumbs up kind of keeps me motivated and that's all for now so I'll see you in the next video

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